1 files changed, 476 insertions, 0 deletions
diff --git a/camel/camel-data-cache.c b/camel/camel-data-cache.c
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+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/* camel-message-cache.c: Class for a Camel cache.
+ *
+ * Authors: Michael Zucchi <notzed@ximian.com>
+ *
+ * Copyright (C) 2001 Ximian, Inc. (www.ximian.com)
+ *
+ * This program is free software; you can redistribute it and/or 
+ * modify it under the terms of version 2 of the GNU General Public 
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ * USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <string.h>
+#include <alloca.h>
+
+#include "camel-data-cache.h"
+#include "camel-exception.h"
+#include "camel-stream-fs.h"
+#include "camel-stream-mem.h"
+#include "camel-file-utils.h"
+
+extern int camel_verbose_debug;
+#define dd(x) (camel_verbose_debug?(x):0)
+
+/* how many 'bits' of hash are used to key the toplevel directory */
+#define CAMEL_DATA_CACHE_BITS (6)
+#define CAMEL_DATA_CACHE_MASK ((1<<CAMEL_DATA_CACHE_BITS)-1)
+
+/* timeout before a cache dir is checked again for expired entries,
+   once an hour should be enough */
+#define CAMEL_DATA_CACHE_CYCLE_TIME (60*60)
+
+struct _CamelDataCachePrivate {
+	GHashTable *busy_stream;
+	GHashTable *busy_path;
+
+	int expire_inc;
+	time_t expire_last[1<<CAMEL_DATA_CACHE_BITS];
+
+#ifdef ENABLE_THREADS
+	GMutex *lock;
+#define CDC_LOCK(c, l) g_mutex_lock(((CamelDataCache *)(c))->priv->l)
+#define CDC_UNLOCK(c, l) g_mutex_unlock(((CamelDataCache *)(c))->priv->l)
+#else
+#define CDC_LOCK(c, l)
+#define CDC_UNLOCK(c, l)
+#endif
+};
+
+static CamelObject *camel_data_cache_parent;
+
+static void data_cache_class_init(CamelDataCacheClass *klass)
+{
+	camel_data_cache_parent = (CamelObject *)camel_type_get_global_classfuncs (camel_object_get_type ());
+
+#if 0
+	klass->add = data_cache_add;
+	klass->get = data_cache_get;
+	klass->close = data_cache_close;
+	klass->remove = data_cache_remove;
+	klass->clear = data_cache_clear;
+#endif
+}
+
+static void data_cache_init(CamelDataCache *cdc, CamelDataCacheClass *klass)
+{
+	struct _CamelDataCachePrivate *p;
+
+	p = cdc->priv = g_malloc0(sizeof(*cdc->priv));
+
+	p->busy_stream = g_hash_table_new(NULL, NULL);
+	p->busy_path = g_hash_table_new(g_str_hash, g_str_equal);
+
+#ifdef ENABLE_THREADS
+	p->lock = g_mutex_new();
+#endif
+}
+
+static void
+free_busy(CamelStream *stream, char *path, void *data)
+{
+	camel_object_unref((CamelObject *)stream);
+	g_free(path);
+}
+
+static void data_cache_finalise(CamelDataCache *cdc)
+{
+	struct _CamelDataCachePrivate *p;
+
+	p = cdc->priv;
+
+	g_hash_table_foreach(p->busy_stream, (GHFunc)free_busy, NULL);
+	g_hash_table_destroy(p->busy_path);
+	g_hash_table_destroy(p->busy_stream);
+
+#ifdef ENABLE_THREADS
+	g_mutex_free(p->lock);
+#endif
+	g_free(p);
+}
+
+CamelType
+camel_data_cache_get_type(void)
+{
+	static CamelType camel_data_cache_type = CAMEL_INVALID_TYPE;
+	
+	if (camel_data_cache_type == CAMEL_INVALID_TYPE) {
+		camel_data_cache_type = camel_type_register(
+			CAMEL_OBJECT_TYPE, "CamelDataCache",
+			sizeof (CamelDataCache),
+			sizeof (CamelDataCacheClass),
+			(CamelObjectClassInitFunc) data_cache_class_init,
+			NULL,
+			(CamelObjectInitFunc) data_cache_init,
+			(CamelObjectFinalizeFunc) data_cache_finalise);
+	}
+
+	return camel_data_cache_type;
+}
+
+/**
+ * camel_data_cache_new:
+ * @path: Base path of cache, subdirectories will be created here.
+ * @flags: Open flags, none defined.
+ * @ex: 
+ * 
+ * Create a new data cache.
+ * 
+ * Return value: A new cache object, or NULL if the base path cannot
+ * be written to.
+ **/
+CamelDataCache *
+camel_data_cache_new(const char *path, guint32 flags, CamelException *ex)
+{
+	CamelDataCache *cdc;
+
+	if (camel_file_util_mkdir(path, 0700) == -1) {
+		camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
+				     _("Unable to create cache path"));
+		return NULL;
+	}
+
+	cdc = (CamelDataCache *)camel_object_new(CAMEL_DATA_CACHE_TYPE);
+
+	cdc->path = g_strdup(path);
+	cdc->flags = flags;
+	cdc->expire_age = -1;
+	cdc->expire_access = -1;
+
+	return cdc;
+}
+
+/**
+ * camel_data_cache_set_expire_age:
+ * @cdc: 
+ * @when: Timeout for age expiry, or -1 to disable.
+ * 
+ * Set the cache expiration policy for aged entries.
+ * 
+ * Items in the cache older than @when seconds may be
+ * flushed at any time.  Items are expired in a lazy
+ * manner, so it is indeterminate when the items will
+ * physically be removed.
+ *
+ * Note you can set both an age and an access limit.  The
+ * age acts as a hard limit on cache entries.
+ **/
+void
+camel_data_cache_set_expire_age(CamelDataCache *cdc, time_t when)
+{
+	cdc->expire_age = when;
+}
+
+/**
+ * camel_data_cache_set_expire_access:
+ * @cdc: 
+ * @when: Timeout for access, or -1 to disable access expiry.
+ * 
+ * Set the cache expiration policy for access times.
+ *
+ * Items in the cache which haven't been accessed for @when
+ * seconds may be expired at any time.  Items are expired in a lazy
+ * manner, so it is indeterminate when the items will
+ * physically be removed.
+ *
+ * Note you can set both an age and an access limit.  The
+ * age acts as a hard limit on cache entries.
+ **/
+void
+camel_data_cache_set_expire_access(CamelDataCache *cdc, time_t when)
+{
+	cdc->expire_access = when;
+}
+
+static void
+data_cache_expire(CamelDataCache *cdc, const char *path, const char *keep, time_t now)
+{
+	DIR *dir;
+	struct dirent *d;
+	GString *s;
+	struct stat st;
+	char *oldpath;
+	CamelStream *stream;
+
+	dir = opendir(path);
+	if (dir == NULL)
+		return;
+
+	s = g_string_new("");
+	while ( (d = readdir(dir)) ) {
+		if (strcmp(d->d_name, keep) == 0)
+			continue;
+
+		g_string_sprintf(s, "%s/%s", path, d->d_name);
+		dd(printf("Checking '%s' for expiry\n", s->str));
+		if (stat(s->str, &st) == 0
+		    && S_ISREG(st.st_mode)
+		    && ((cdc->expire_age != -1 && st.st_mtime + cdc->expire_age < now)
+			|| (cdc->expire_access != -1 && st.st_atime + cdc->expire_access < now))) {
+			dd(printf("Has expired!  Removing!\n"));
+			unlink(s->str);
+			if (g_hash_table_lookup_extended(cdc->priv->busy_path, s->str, (void **)&oldpath, (void **)&stream)) {
+				g_hash_table_remove(cdc->priv->busy_path, path);
+				g_hash_table_remove(cdc->priv->busy_stream, stream);
+				g_free(oldpath);
+			}
+		}
+	}
+	g_string_free(s, TRUE);
+	closedir(dir);
+}
+
+/* Since we have to stat the directory anyway, we use this opportunity to
+   lazily expire old data.
+   If it is this directories 'turn', and we haven't done it for CYCLE_TIME seconds,
+   then we perform an expiry run */
+static char *
+data_cache_path(CamelDataCache *cdc, int create, const char *path, const char *key)
+{
+	char *dir, *real, *tmp;
+	guint32 hash;
+
+	hash = g_str_hash(key);
+	hash = (hash>>5)&CAMEL_DATA_CACHE_MASK;
+	dir = alloca(strlen(cdc->path) + strlen(path) + 8);
+	sprintf(dir, "%s/%s/%02x", cdc->path, path, hash);
+	if (access(dir, F_OK) == -1) {
+		if (create)
+			camel_file_util_mkdir(dir, 0700);
+	} else if (cdc->priv->expire_inc == hash
+		   && (cdc->expire_age != -1 || cdc->expire_access != -1)) {
+		time_t now;
+
+		dd(printf("Checking expire cycle time on dir '%s'\n", dir));
+
+		now = time(0);
+		if (cdc->priv->expire_last[hash] + CAMEL_DATA_CACHE_CYCLE_TIME < now) {
+			data_cache_expire(cdc, dir, key, now);
+			cdc->priv->expire_last[hash] = now;
+		}
+		cdc->priv->expire_inc = (cdc->priv->expire_inc + 1) & CAMEL_DATA_CACHE_MASK;
+	}
+
+	tmp = camel_file_util_safe_filename(key);
+	real = g_strdup_printf("%s/%s", dir, tmp);
+	g_free(tmp);
+
+	return real;
+}
+
+static void
+stream_finalised(CamelObject *o, void *event_data, void *data)
+{
+	CamelDataCache *cdc = data;
+	char *key;
+
+	CDC_LOCK(cdc, lock);
+	key = g_hash_table_lookup(cdc->priv->busy_stream, o);
+	if (key) {
+		g_hash_table_remove(cdc->priv->busy_path, key);
+		g_hash_table_remove(cdc->priv->busy_path, o);
+		g_free(key);
+	}
+	CDC_UNLOCK(cdc, lock);
+}
+
+/**
+ * camel_data_cache_add:
+ * @cdc: 
+ * @path: Relative path of item to add.
+ * @key: Key of item to add.
+ * @ex: 
+ * 
+ * Add a new item to the cache.
+ *
+ * The key and the path combine to form a unique key used to store
+ * the item.
+ * 
+ * Potentially, expiry processing will be performed while this call
+ * is executing.
+ *
+ * Return value: A CamelStream (file) opened in read-write mode.
+ * The caller must unref this when finished.
+ **/
+CamelStream *
+camel_data_cache_add(CamelDataCache *cdc, const char *path, const char *key, CamelException *ex)
+{
+	char *real, *oldpath;
+	CamelStream *stream;
+
+	CDC_LOCK(cdc, lock);
+
+	real = data_cache_path(cdc, TRUE, path, key);
+	if (g_hash_table_lookup_extended(cdc->priv->busy_path, real, (void **)&oldpath, (void **)&stream)) {
+		g_hash_table_remove(cdc->priv->busy_path, oldpath);
+		g_hash_table_remove(cdc->priv->busy_stream, stream);
+		unlink(oldpath);
+		g_free(oldpath);
+	}
+
+	stream = camel_stream_fs_new_with_name(real, O_RDWR|O_CREAT|O_TRUNC, 0600);
+	if (stream) {
+		camel_object_hook_event((CamelObject *)stream, "finalize", stream_finalised, cdc);
+		g_hash_table_insert(cdc->priv->busy_stream, stream, real);
+		g_hash_table_insert(cdc->priv->busy_path, real, stream);
+	} else {
+		g_free(real);
+	}
+
+	CDC_UNLOCK(cdc, lock);
+
+	return stream;
+}
+
+/**
+ * camel_data_cache_get:
+ * @cdc: 
+ * @path: Path to the (sub) cache the item exists in.
+ * @key: Key for the cache item.
+ * @ex: 
+ * 
+ * Lookup an item in the cache.  If the item exists, a stream
+ * is returned for the item.  The stream may be shared by
+ * multiple callers, so ensure the stream is in a valid state
+ * through external locking.
+ * 
+ * Return value: A cache item, or NULL if the cache item does not exist.
+ **/
+CamelStream *
+camel_data_cache_get(CamelDataCache *cdc, const char *path, const char *key, CamelException *ex)
+{
+	char *real;
+	CamelStream *stream;
+
+	CDC_LOCK(cdc, lock);
+
+	real = data_cache_path(cdc, FALSE, path, key);
+	stream = g_hash_table_lookup(cdc->priv->busy_path, real);
+	if (stream) {
+		camel_object_ref((CamelObject *)stream);
+		g_free(real);
+	} else {
+		stream = camel_stream_fs_new_with_name(real, O_RDWR, 0600);
+		if (stream) {
+			camel_object_hook_event((CamelObject *)stream, "finalize", stream_finalised, cdc);
+			g_hash_table_insert(cdc->priv->busy_stream, stream, real);
+			g_hash_table_insert(cdc->priv->busy_path, real, stream);
+		}
+	}
+
+	CDC_UNLOCK(cdc, lock);
+
+	return stream;
+}
+
+/**
+ * camel_data_cache_remove:
+ * @cdc: 
+ * @path: 
+ * @key: 
+ * @ex: 
+ * 
+ * Remove/expire a cache item.
+ * 
+ * Return value: 
+ **/
+int
+camel_data_cache_remove(CamelDataCache *cdc, const char *path, const char *key, CamelException *ex)
+{
+	CamelStream *stream;
+	char *real, *oldpath;
+	int ret;
+
+	CDC_LOCK(cdc, lock);
+
+	real = data_cache_path(cdc, FALSE, path, key);
+	if (g_hash_table_lookup_extended(cdc->priv->busy_path, real, (void **)&oldpath, (void **)&stream)) {
+		g_hash_table_remove(cdc->priv->busy_path, path);
+		g_hash_table_remove(cdc->priv->busy_stream, stream);
+		g_free(oldpath);
+	}
+
+	/* maybe we were a mem stream */
+	if (unlink(real) == -1 && errno != ENOENT) {
+		camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM,
+				     _("Could not remove cache entry: %s: %s"),
+				     real, strerror(errno));
+		ret = -1;
+	} else {
+		ret = 0;
+	}
+
+	g_free(real);
+
+	CDC_UNLOCK(cdc, lock);
+
+	return ret;
+}
+
+/**
+ * camel_data_cache_rename:
+ * @cache: 
+ * @old: 
+ * @new: 
+ * @ex: 
+ * 
+ * Rename a cache path.  All cache items accessed from the old path
+ * are accessible using the new path.
+ *
+ * CURRENTLY UNIMPLEMENTED
+ * 
+ * Return value: -1 on error.
+ **/
+int camel_data_cache_rename(CamelDataCache *cache,
+			    const char *old, const char *new, CamelException *ex)
+{
+	/* blah dont care yet */
+	return -1;
+}
+
+/**
+ * camel_data_cache_clear:
+ * @cache: 
+ * @path: Path to clear, or NULL to clear all items in
+ * all paths.
+ * @ex: 
+ * 
+ * Clear all items in a given cache path or all items in the cache.
+ * 
+ * CURRENTLY_UNIMPLEMENTED
+ *
+ * Return value: -1 on error.
+ **/
+int
+camel_data_cache_clear(CamelDataCache *cache, const char *path, CamelException *ex)
+{
+	/* nor for this? */
+	return -1;
+}